The invention pertains to a method for pattern recognition and validation, especially of hand-written signatures, said are written remote from the place of recognition and validation, using a computer system. The invention furthermore pertains to an arrangement for performing this method as well as to the use of the method and the arrangement in a signature verification environment such as preferably in the banking area.
In U.S. Pat. No. 4,028,674 a signature verification where an image mosaic for a signature to be verified is stored in a memory and wherein a prototype feature set for said signature is stored in a memory, is described. Binary signals representative of the location and magnitude of positive and negative peaks in mosaic and the stroke character in the region of each of said peaks are generated. A two-dimensional feature set pattern after the prototype set is stored with the signals ordered in dependance upon the occurrence of the peaks in the signature and accompanied by peak rank in terms of peak magnitude and stroke character in the vicinity of each peak. The feature vector set is then compared with the prototype vector set and identity is signalled when within predetermined limits the feature set matches the prototype set.
U.S. Pat. No. 4,286,255 describes a method and apparatus for determining whether a newly-signed signature and previously recorded signature were made by the same person. The method and apparatus include the steps of an apparatus for scanning a document containing the newly-signed signature to provide an electrical signal representative of the reflectivity of the newly-signed signature and the document and generating a signature envelope derived from the electrical signal with the plurality of characteristics of the newly-signed signature are then calculated based on the location and magnitude of the selected points forming the signature envelope with respect to a reference line. The calculated characteristics of the newly-signed signature are then compared with corresponding characteristics of a standard signature formed from a group of previously recorded signatures and a signature verification decision is generated based on the degree with which the compared characteristics match.
From the co-pending European application EP 90 120 620.1 (IBM Docket GE 990 010) of the present applicant, a method of automatically verifying a signature of an individual with a computer is described. In this known method a digitized image with a number of picture elements is established from the signature to be verified. Parameter values to be verified are calculated from this digitized image and are compared with corresponding reference parameter values that were calculated and stored previously. Depending on a comparison of the reference parameter values and the parameter values to be verified, it is decided if the signature to be verified is true or false. Various possibilities are described in this pending application for the calculation of significant parameters. The gravity-center of all densities of all rows and all columns of the digitized image is a parameter which can be used for a preselection. Centers-of-gravity, gravity-lines, maximum values and maximum lines, etc. are further significant parameters. Parameters with a very high reliability can be generated by calculating second order polynomials which describe segments of the signature.
The general problem underlying signature verification or more generally spoken, pattern recognition and validation pertains to the fact that an image typically has a very high amount of information. Analyzing all the information is very time-consuming and at least may lead to confusion at most cases information which are of no or minor interests. But this information which is of no interests makes very often identification of the important information very difficult. Under statistical considerations in many cases the distribution is so wide that the desired information cannot be detected.